Resolution-enhanced Fourier ptychographic microscopy based on high-numerical-aperture illuminations

Area of Science:

• Optics and Photonics
• Microscopy
• Computational Imaging

Background:

• Conventional microscopy faces a trade-off between spatial resolution and field-of-view (FOV), limited by the optical system's space-bandwidth product (SBP).
• Fourier ptychography microscopy (FPM) decouples resolution and FOV but is typically limited to numerical apertures (NA) between 0.4-0.7.
• High-throughput screening and digital pathology demand both high resolution and wide FOV imaging.

Purpose of the Study:

• To introduce a novel high-NA illumination-based resolution-enhanced FPM (REFPM) platform.
• To overcome the NA limitations of conventional FPM systems.
• To achieve simultaneous high resolution and wide FOV imaging.

Main Methods:

• Developed a REFPM platform utilizing a LED-array-based digital oil-immersion condenser.
• Employed high-angle programmable plane-wave illuminations.
• Integrated a 10×, 0.4 NA objective lens to achieve an effective imaging performance of 1.6 NA.

Main Results:

• Achieved a half-pitch resolution of 154 nm at 435 nm wavelength.
• Demonstrated imaging across a wide FOV of 2.34 mm².
• Reached a space-bandwidth product (SBP) of 98.5 megapixels, approximately 50 times higher than conventional microscopes with similar resolution.

Conclusions:

• The REFPM platform significantly enhances resolution and broadens the FOV compared to conventional oil-immersion microscopes.
• This advancement represents a key step for FPM in high-resolution, large-NA imaging applications.
• The developed technique offers a promising solution for applications requiring both detailed imaging and extensive sample coverage.